US2176453A

US2176453A - Process and apparatus for treating hydrocarbon material

Info

Publication number: US2176453A
Application number: US119817A
Authority: US
Inventors: Jr Lincoln Clark
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-01-09
Filing date: 1937-01-09
Publication date: 1939-10-17
Anticipated expiration: 1956-10-17

Description

L. CLARK, JR

Oct. 17, 1939.

PROCESS AND APPARATUS FOR TREATING HYDROCARBON MATERIAL Filed Jan. 9, 1937 xmxmgtmqaw \wmcn uxm mat SQ ti Patented Oct. 17, 1939 PROCESS AND APPARATUS FOR TREATING HYDROCARBON MATERIAL Lincoln Clark, Jr., Pasadena, Calif., assignor to Lincoln Clark,

Application January 9,

9 Claims.

This invention relates to the treatment of hydrocarbon materials, particularly by direct contact with heat carrying gases, for purposes of cracking or reacting said hydrocarbon materials and more specifically it relates to a means or method of improving the simplicity and efiiciency under which the operation of such treatment is conducted.

It has been my experience in the development of the process disclosed in United States Patent #1,491,518 issued to Lincoln Clark April 22, 1924, that in the operation of the refractory lined chambers wherein combustion gases are generated under pressure and subsequently contacted and/or mixed with the hydrocarbon materials to be treated, any substantial pressure drop in the flow of materials between the point of combustion and a point immediately following the point of contact of gases and hydrocarbons will cause leaks within the refractory and insulating linings of chambers due to structural limitations of said linings. It is necessary that the zones of combustion and hot gas transfer be lined with highly refractory materials and in order to properly insulate such zones'a variety of materials of different refractory and insulating values are required. These materials have diiierent expansion and contraction coefficients which fact makes it impossible to be assured that no spaces exist between the materials themselves or between the materials and the steel shells of the chambers. Any leaks through said chamber linings which may develop during operation not only cause disintegration of the lining materials but also interfere with the working of the process.

In the mixing of hydrocarbon vapors with high temperature gases it has been found that excessive quantities of undesirable fixed gas are formed at the point of contact and/or mixing unless the velocities of the gas and vapor streams is very high, with the resulting turbulence causing an almost instantaneous mixture. In previous work I have accomplished mixing in a tubular refractory duct as a reduced diameter extension of the combustion zone. The duct was insulated in a steel nozzle leading from the combustion chamber. Hydrocarbon vapors were introduced into the hot gas stream flowing through the duct by means of a side inlet. As the vapors issued from the side inlet into the high velocity gas stream their path .was diverted and the flow suddenly increased to a high velocity. The energy to accomplish this change of motion was derived from the hot gases in which it appeared as pressure head and gave a pressure drop of 3 to 5 lbs/sq. in. across Pasadena, Calif.

1937, Serial No. 119,817

the point of vapor admission. Under these conditions a minimum of fixed gas was formed at the point of contact but the high velocities and pressure drops soon caused leaks within the linings of the combustion chamber and nozzles, deterioration of the linings, hot spots on the steel shells and the necessary shut down of the unit. In order to maintain continuous operation over long periods of time it was necessary to increase the diameter of the mixing tube. Lower velocities reduced the pressure drop to a point at which the leaks were not bothersome but the fixed gas loss became excessive with lower process efiiciency, economy and controllability.

I have discovered that it is possible to obtain the high velocity necessary for good mixing of hydrocarbon materials and hot gases without the problem of excessive pressure drops and resultant leaks within the linings, by introducing the hydrocarbon materials at high velocities into the relatively motionless hot gases and removing said gases and hydrocarbons together with the hot gases from the zone of original contact at a high velocity and without substantially altering the direction of flow of the hydrocarbons. Further it is possible to efliciently carry out the two operations of generating combustion gases and contacting them with the hydrocarbons within the one refractory lined vessel, thereby simplifying the construction of the apparatus in which the treatment is efiected and materially decreasing the possibility of leaks by lowering the distance travelled by the hot gases prior to their contact with the hydrocarbons and by reducing the work upon the hydrocarbons by the hot gases.

Since the object of this invention is to provide a process for treating hydrocarbon materials by direct contact with hot combustion gases for purposes of converting said hydrocarbons which process consists in generating hot combustion gases under superatmospheric pressure, in contacting hydrocarbon materials with said combustion gases in a simple and efficient manner, in reacting or converting said hydrocarbon materials and in recovering the resultant products, the conditions of treatment and/or the operations to which the mixture of gases and hydrocarbons may be subjected after their mixing may be greatly varied in accordance with requirements and properties of materials and products. No particular design is required.

The incorporation into a complete unit of such well known operations as scrubbing, heat exchange, distillation, condensing and/or absorption will effect the recovery of the products of treatment but the entire process is ineificient and problematical unless the generation of the hot gases and the mixing of the hydrocarbon materials therewith is carried out in a simple, efficient and dependable manner.

I Will now show a form of apparatus that illustrates how this invention may be carried into practical effect, the illustration being in elevation and diagrammatical:

I designates a chamber in which gases of combustion ranging in temperature from between 1500 F. and 3700 F. and above are produced under pressures varying from 7 to 350 pounds or above, the pressure therein substantially determining the pressure maintained in-the system, air or oxygen to support combustion in the chamber I being supplied by the compressor 6 through receiver I, control valve 8 and line 9 with fuel oil being supplied to the burner I2 through line It and valve II. Steam or other materials which may or may not effect the combustion or treatment of the hydrocarbons may be introduced by means of line I3 and valve I4. Hydrocarbon vapors are introduced into chamber I through nozzle I and are removed from the chamber together with the combustion gases by means of the refractory mixing tube I I in the steel nozzle I8. All materials leaving the chamber I through the mixing tube I! are passed through the reaction chamber or zone I9, and subsequently subjected to whatever operations or apparatus is desired in recovering the products or treatment such as heat exchanger 20, condenser 2|, liquid accumulator 22 and absorber 23. By means of valve 25 in line 24 leading from the absorber 23, the pressure of the entire system ahead of this valve may be regulated, so also the flow of gases. I

The hydrocarbon material to be treated is passed through heat exchanger 26 and heater 26 to the flash drum 2! from which non-volatile material is removed by means of line 28. Steam or gas to assist in vaporization is introduced through line 29 and heater 26 into the flash drum Z'I. Gases and vapors leaving the top of the flash drum 2'! through line 30 are passed through the superheater 3|, transfer line 32 and nozzle I5 into the outlet end of the chamber I.

As illustrated, mixing tube I1 is elongated, and its length preferably is many times its mean cross sectional dimensions, i. e. its diameter, when of circular cross section. Being so elongated, tube I'I serves to produce a thorough and complete admixture of gas and vapors prior to their delivery to the reaction chamber.

Referring to the chamber I in which the hot gases are generated by combustion or air or oxygen supplied by line 9 and fuel supplied by line-I0. The chamber is composed of a high temperature lining 3 backed up by refractory and monolithic insulating 4 tightly rammed into the steel shell 2. The lining 3 is preferably cast and vitrified before being put in place in order to assure a minimum of leaks. Similarly, the protecting tube I6 and mixing tube I! are preferably cast and vitrified prior to being put'in place. The purpose of the tube I6 is to protect the metal vapor nozzlefrom the direct action of the hot gases and to permit the removal of the nozzle I5 for repair. or replacement without endangering the strength or tightness of the refractory assembly. The purpose of the mixing tube placed diametrically opposite the vapor nozzle I6 and on the same axis is to remove all materials from the chamber and to produce a homogeneous gaseous mixture of the materials issuing therefrom. In order to insure the removal of all materials through the mixing tube I I and to prevent leakage of gases or vapors from the tube into the insulation 4' between tube I! and nozzle I8 and thence into the reaction chamber or zone, the tube is preferaby in one cylindrical piece and tightly sealed into the steel nozzle I8 by the'insulation 4' which is an integral part of the chamber insulation 4.

The combustion takes place substantially adiabatically Within the chamber, the insulation reducing the heat losses as much as possible, usually to 2 to 8 per cent. The combustion of air or oxygen and fuel starts in zone I. As the gases pass through zone I the combustion reaction is completed and the gases are substan tially devoid of oxygen. The pressure drop occurring in the flow of gases between zones I and I" is negligible due to the relatively slow velocity. m

The hydrocarbon gases or vapors introduced into the combustion gases through nozzle I5 surrounded by the refractory protecting tube It, are moving at a high velocity ranging from 100 to 150 feet per second or more. The higher the velocity, the better will be the mixing operation. Velocities higher than 250 feet per second cause an excessive drop in passage of vapors through the nozzle I5, which pressure drop, although taking place within the metal nozzle I5 and thereby causing no leaks Within the refractory linings of the chamber, nevertheless, tends tosuppress vaporization in the flash drum 2'! and is therefore undesirable.

As the hot gases and vapors enter the mixing tube I! a pressure drop in the hot gases occurs as their velocity is increased to 100 to 250 feet per second or higher. This pressure drop is low however due to the low density of the hot gases. With a tight chamber of the type disclosed and a well sealed mixing tube assembly this low pressure drop should cause no leaks in the linings.

If the hydrocarbon vapor velocity is equal to or.

higher than that of the hot gases at the point of entranceinto the mixing tube I! the pressure drop in hot gas flow will be solely. that caused by a change of velocity' or will be reduced by the injector action of the high velocity vapor stream. If the vapor velocity from the nozzle I5 is lower than that of the hot gases entering the tube I1, the hot gases must perform the additional work of increasing the vapor velocity to the mix velocity with increased pressure drop in hot gas flow and the resulting danger from leaks. It is'my intention to maintain a vapor velocity higher than that of the hot gases but because of the fact that vapor Velocity is determined by design and cannot be controlled 7 with variations in volumes, quantities and services to which the apparatus may be subjected in commercial use, I do not wish to be limited theretor As the stream of hot gases and hydrocarbon vapors enters the mixing tube the velocities are sufiicient to cause an extremely turbulent flow with almost instantaneous mixing or blending of the two streams. This instantaneous blending minimizes overheating or" parts, of the hydrocarbon vapors, reduces undesirablel fixed gas formation and uncontrolled cracking'in the mixing zone, with the result that the entire cracking reaction takes place controllably within the reaction chamber assuring flexible operation, max imum yields and a high process efflciency.

It is believed that the conditions responsible for elimination of gas by-pass from the combustion chamber through the refractory walls of the apparatus, will be understood from the foregoing. This result is accomplished primarily because of the fact that static pressure within the combustion chamber is not relied upon to force the gas-vapor mixture through the mixing passage. Due to the length and cross sectional size of the mixing passage required for rapid and thorough admixing of the gases and vapors, a substantial and relatively great differential between the combustion chamber and reaction chamber pressures would be necessary to maintain proper rate of flow through the mixing passage, if the flow were to be produced solely by differences in static pressures at opposite ends of the passage. Experience has shown that under such conditions it is impossible, at least after the equipment has been in use for any considerable length of time, to avoid leakage of combustion gases between the difierential pressure chambers through the refractory lining.

In accordance with the invention, I am able to maintain relatively low static pressure within the combustion chamber, tothe point of avoiding any differential between the static pressures of the reaction chamber and combustion chamber (the static pressure in the latter may even be less than the reaction chamber pressure) that would resultin a tendency for the combustion gases to by-pass the mixing tube. I project the vaporized hydrocarbons into the open end of the mixing passage at a rate such that the combustion gases are drawn into the mixing tube and the mixed vapors and gases are caused to flow through the tube, not by virtue of static pressure differential at its ends, but because of the energy and velocity force of the projected vapor stream. Being drawn out of the combustion chamber, the gases must flow into the mixing tube, and not through any interstices in the refractory wall surrounding it.

Although the words hydrocarbon vapors and hydrocarbon materials have been used interchangeably in these disclosures, I wish it understood that the hydrocarbon materials introduced into the, hot gases by means of nozzle l5 may be in the states of liquid, semi-liquid, vapors or gases and still conform to the specifications for this invention. In the example hydrocarbon vapors were shown but I do not wish to be limited strictly thereto.

carbon materials depending upon the physical and chemical properties of the added materials. The controllability of the effect of these added materials upon the hydrocarbon will be directly dependent upon the highly efficient form of mixing and reacting in the process disclosed.

What I claim is:

1. In oil conversion apparatus, the combination comprising walls of refractory material forming an elongated gas chamber and an elongated mixing passage having an inlet leading from said chamber at one end thereof, said passage extending in a direction transversely of the axis of said chamber, the length of said passage being a plurality of times its transverse mean cross sectional dimension, an enlarged reaction chamber communicating with said passage, means for generating hot combustion gases within said chamber toward the end thereof opposite the first mentioned end, and means for projecting a high velocity stream of hydrocarbon vapors through an opening substantially smaller than said mixing passage inlet and thence in a straight path through an open portion of said gas chamber occupied by the combustion gases directly into said inlet, so that the projected vapor stream draws combustion gases from the gas chamber into the mixing passage and maintains a relatively low differential between the pressures in said gas chamber and reaction chamber.

2. In oil conversion apparatus, the combination comprising refractory walls forming an elongated gas chamber, an elongated refractory tube forming a mixing passage extending from one side of said chamber in a directiontransversely of its axis, the length of said passage being a plurality of times its diameter, an enlarged reaction chamber communicating with said passage, means for generating hot combustion gases within said gas chamber at a point spaced longitudinally from said mixing passage inlet, a nozzle in the gas chamber wall opposite said inlet and having a discharge opening substantially smaller than said inlet, and means for discharging hydrocarbon vapors at high velocity from said nozzle in a straight path through the gas chamber directly into said inlet, so that the projected vapor stream draws combustion gases from the gas chamber into the mixing passage and maintains a relatively low differential between the pressures in said gas chamber and reaction chamber.

3. In oil conversion apparatus, the combination comprising walls of refactory material form.- ing a gas chamber and an elongated mixing passage having an inlet leading from said chamber, the length of said passage being a plurality of times its transverse mean cross sectional dimension, an enlarged reaction chamber communicating with said passage, means for supplying hot gases to said gas chamber, and means for projecting a high velocity stream of hydrocarbon vapors through an opening substantially smaller than said mixing passage inlet and thence in a straight path through an open portion of said gas chamber occupied by the hot gases directly into said inlet, so that the bulk of the hydrocarbon vapors are prevented from diffusing within said gas chamber and the projected vapor stream draws hot gases from the gas chamber into the mixing passage and maintains a relatively low differential between the pressures in said gas chamber and reaction chamber.

4. In oil conversion apparatus, the combination comprising walls of refractory material forming a gas chamber and an elongated mixing passage having an inlet leading from said chamber, said passage extending in substantially straight alinement with said inlet and the length of said passage being a plurality of times its transverse mean cross sectional dimension, an enlarged reaction chamber communicating with said passage, means for supplying hot gases to said gas chamber, and means for projecting a high velocity stream of hydrocarbon vapors through an opening substantially smaller than said mixing passage inlet and thence in a straight path through an open portion of said gas chamber occupied by the hot gases directly into and in alinement with said inlet, so that the bulk of the hydrocarbon vapors are prevented from diffusing within said gas chamber and the projected vapor stream draws hot gases from the gas chamber into the mixing passage and maintains a relatively low differential between the pressures in said gas chamber and reaction chamber.

5. Inoil conversion apparatus, the combination comprising a refractory tube forming a gas chamber and an elongated refractory tube forming a mixing passage having an inlet leading from said chamber, the length of said passage being a plurality of times its diameter, refractory material at the outside of said tube, an enlarged reaction chamber communicating with said passage, means for supplying hot gases to said gas chamher, and means for projecting a high velocity stream of hydrocarbon vapors through an opening substantially smaller than said mixing passage inlet and'thence in a straight path through an open portion of said gas chamber occupied by the hot gases directly into said inlet, so that the bulk of the hydrocarbon vapors are prevented from diffusing within said gas chamber and the projected vapor stream draws hot gases from the gas chamber into the mixing passage and maintains a relatively low differential between the pressures in said gas chamber and reaction chamher.

6. The method of converting petroleum hydrocarbons within a refractory lined retort that in-' cludes, maintaining hot gases at low velocity of flow within an enlarged gas zone, discharging a stream of hydrocarbon vaporsat high velocity in a straight path from a comparatively small opening into an open portion of said zone occupied by the gases and into a comparatively large opening forming the inlet end of an elongated mixing passage whose length is a plurality of times its mean cross sectional dimension, Without permitting diffusion of the bulk of said vapors within said zone, passing the resultant 1 gas and vapor mixture from said passage into an enlarged reaction zone, and finally recovering ccndensible hydrocarbons, said high velocity vapor stream operating to draw hot gases from said gas zone into the mixing passage so that a relatively low difierential is maintained between the pressures in said gas zone and reaction zone. I

7 The method of converting petroleum hydrocarbons within a refractory lined retort that includes, maintaining hot gases at low velocity of flow within an enlarged zone, projecting a stream of hydrocarbon vapors at high velocity in a straight path from a comparatively small opening at one side of said zone into an open portion of said zone occupied by the gases andinto a comparatively largeopening at the opposite side of said zone and forming the inlet end of an elongated mixing passage whose length is a plurality of times its mean cross sectional dimen-' sion, thereby causing the projected'vapor stream to draw hot gases from said zone into the mixing passage wherein the combined gases and vapors are admixed in a turbulent stream but without permitting diffusion of the bulk of said vapors within said zone, passing the resultant gas and vapor mixture from said passage into an enlarged reaction zone, and finally recovering condensible hydrocarbons.

8. The method of converting petroleum hydrocarbons within a refractory lined retort that includes, maintaining hot combustion gases at low velocity of flow within an enlarged zone, projecting a stream of hydrocarbon vapors at 'high velocity in a straight path, from a comparatively small opening into an open portion of said zone occupied by the gases and into a comparatively large opening forming the inlet end of an elongated mixing passage whose length is a plurality of times its mean cross sectional dimension, thereby causing the projected vapor stream to draw combustion gases from said zone into the mixing passage wherein the combined gases and vapors are admixed in a turbulent stream but without permitting diffusion of the bulk of said vapors Within said zone, said passageext'ending substantially in alinement with the direction of flow of the hydrocarbons discharged from the first mentioned opening, passing the resultant gas and vapor mixture from said passage into an enlarged reaction zone, and finally recovering condensible hydrocarbons. A i

9. The method of converting petroleum hydrocarbons within a refractory lined retort that includes, generating combustion gases within an enlarged zone and maintaining the gases at com paratively low velocity of flow therein,'projecting a stream of hydrocarbon Vapors at high velocity in a straight path from a comparatively small opening into an open portion of said zone cupied by the gases and into a comparatively large opening forming the inlet end'of' an elongated'mixing passage whose length is a plurality of times its mean cross sectional dimension, thereby causing the projected vapor stream to draw combustion gases from said 'zone into the mixing passage wherein the combined gases and vapors are admixed in a turbulent stream but without permitting diffusion of the bulk of said vapors within said zone, passing the resultant gas and vapor mixture from said passage into an enlarged reaction zone, and finally recovering condensible hydrocarbons.

' LINCQLN CLARK, JR.